Statistical Analysis Of The Propagation And Evolution Of Coronal Mass Ejections In Interplanetary Space

Coronal mass ejections(CMEs)are the main source of disturbances of the near-Earth space environments.Studying the long-range propagation and evolution of CMEs in the heliosphere is of great significance to understand space weather phenomena and to improve the ability of space weather forecasting.In this dissertation,based on remote sensing and multi-point in situ solar wind observations,the authors analyze the kine-matics of fast CMEs/shocks in the Sun-Earth space and then beyond one astronomical unit(au)and their associated geoeffectiveness.Two fast CMEs that erupted on 2005 May 6 and 13 have been studied first in this work.We use a graduated cylindrical shell(GCS)model to fit the coronagraph obser-vations from SOHO/LASCO.Then we track the evolution of the CME/shock inside 1au by applying the frequency drift of an interplanetary type II radio burst.And finally we employ a one dimensional(1D)magnetohydrodynamic(MHD)model to propagate the near-Earth solar wind disturbances to Ulysses,and a 1D kinematic model to quan-tify the kinematic parameters of the CME/shock in the Sun-Earth space and verify their propagation beyond 1 au.Conclusions are as follows:(1)by comparing the speeds near the Sun,near the Earth,and at Ulysses of these two CMEs/shocks respectively,we find that they all completed their major deceleration before arriving at the Earth,and then propagated outward with a gradual deceleration beyond 1 au?(2)the shock propagation profile obtained from the 1D kinematic model is consistent well with all the data,except that it is a little lower than the Ulysses location when the interplanetary CME(ICME)arrived there? the shock deceleration cessation distance yielded from the kinematic model(just for the May 13 case)is about 0.52 au,further confirming that the shock had its major deceleration take place in the Sun-Earth space?(3)although the eruption times of these two CMEs were separated by about one week,they could still interact with each other in interplanetary space since their source regions were in similar directions,and two ICMEs were observed at Ulysses?(4)when they arrived at the Earth,the southward magnetic field components in the shock/ICME sheath region caused intense geomagnetic storms,stressing the critical role of the sheath region in geomagnetic storm generation.Then we carry out a kinematic analysis of seven fast CMEs in solar cycle 23.The GCS model,frequency drift of interplanetary type II radio bursts,and the 1D MHD model have been applied to obtain the CME/shock propagation parameters near the Sun,in the Sun-Earth space,and then beyond 1 au,respectively? an analytical model without free parameters is used to quantify the kinematic parameters inside 1 au for each case and the acquired propagation profile has been extended to the distance of Ulysses in order to show whether it is consistent with the shock propagation beyond the Earth.Key results are as follows:(1)the major deceleration for each case is finished inside 1 au,and thereafter the shock is slowly decelerated to Ulysses?(2)the resulting propagation profile for each event agrees with the distances obtained from the GCS fit near the Sun and the frequency drift of interplanetary type II radio bursts between the Sun and the Earth,and is roughly consistent with the 1D MHD model results and the in situ solar wind observations at Ulysses,which suggests the usefulness of the analytical model? the deceleration cessation distances for all events are inside 0.6 au,which proves that the shocks ceased their rapid deceleration in the Sun-Earth space?(3)correlations of the kinematic parameters for all events manifest that a faster CME tends to decelerate rapidly in a shorter time period?(4)for several of these events,the associated geomagnetic storms were mainly caused by the southward magnetic field components in the sheath region? in particular,when a CME-driven shock is propagating into a preceding ICME,the preexisting southward magnetic field components inside the ICME can be significantly amplified by the shock and gives rise to a severe geomagnetic storm.The novelty and uniqueness of this dissertation are as follows:(1)based on coronagraph observations,interplanetary type II radio bursts,and multi-point in situ solar wind observations,and by combining the GCS model,1D MHD model,and 1D kinematic model,the authors can continuously track a CME/shock from the Sun to interplanetary space,which is of great significance to understand the CME propagation and evolution in interplanetary space?(2)the authors analyze the long-range propagation and evolution of multiple fast CMEs from the Sun to the Earth and then beyond 1 au.The results confirm that fast CMEs finished their major deceleration before reaching 1 au and then propagated out-ward with a gradual deceleration,which is of particular significance to further under-stand their space weather effects?(3)the authors reveal a tendency from a statistical sense that the faster the CME,the larger the deceleration,and the shorter the deceleration time period within 1 au,which can help improve the ability of space weather forecasting and enhance our understanding of solar storms.